Compounds of the type prepared by the method of the present invention are known, for example see U.S. Pat. No. 3,830,803. These compounds are useful physiologically active substances.
The use of 2-(N-hydroxyethyl-N-lower alkylaminomethyl)-benzhydrols to prepare benz[ f]-2,5-oxazocine compounds and use of p-toluene sulfonic acid and of potassium t-butoxide as cyclizing agents in the process for making these compounds have been described (see, for example, Canadian Pat. No. 863,349). However, those methods do not provide high yields of the desired product probably because of the formation of by-products. The mechanism of the cyclization used in the process of the present invention is substantially different from any method for production of those compounds heretofore described. In the present method, the benzhydrol compound is treated with aqueous hydrogen halide, which appears to bring cyclization through replacement of the benzhydrol hydroxy group by halogen and/or formation of a carbonium ion which is followed by cyclization to the desired 8-membered ring.